The present invention relates to coke treatments in general and, in particular, to a new and useful arrangement for dry cooling glowing coke in a closed chamber with recovery of the sensible heat, where the coke gives off its heat partly directly to an inert circulating gas and partly indirectly over cooling surfaces to a cooling liquid.
A number of dry coke cooling methods are known where the sensible heat of the coke is removed in a cooling shaft by a circulating, possible inert gas which gives off its heat to a following steam boiler.
A compilation of various methods working on this principle, as well as the necessary equipment can be found in "Glueckauf" 114 (1978) No. 14, p. 611 ff.
In the course of the last years, dry coke cooling plants have gained importance where the coke is at first introduced in charges into an antechamber arranged above the cooling chamber proper, from where it flows continuously into the cooling chamber underneath, depending on the discharge rate of the completely cooled coke, e.g., according to German Auslegungschrift Nos. 2,432,025 and 1,471,589. With an irregular coke yield, e.g., due to a breakdown in the conveyor system, the cooling of the coke with the resulting generation of steam can be kept constant for some time by means of the antechamber. The cooling of the coke in the cooling chamber is effected exclusively by direct heat exchange with the inert circulating gas blown in counterflow through the coke charge, which gives off the absorbed heat again directly or indirectly, to other media.
In this type of cooling, it is necessary to blow and circulate very large amounts of cooling gas through the coke charge. Particularly the high cooling gas velocities at the upper, outer end of the cooling chamber have the effect in the known cooling devices that considerable amounts of coke dust must be deposited to avoid excessive wear and fouling of the lines and equipment.
According to German Auslegungschrift No. 1,471,589, the gas drain system between antechamber and cooling tank consists of channels distributed over the entire circumference of the chamber and extending obliquely upward, and of a ring conduit arranged around the antechamber into which the channels open. After issuing from the coke charge, the gas is conducted immediately through a few small brick channels at high speed into the ring conduit. Cleaning of these channels is practically impossible.
In addition to these methods and arrangements for dry coke cooling with direct heat exchange of the coke and circulating gas, an arrangement for the dry quenching of coke in a closed chamber which is surrounded by water cooling pipes is known from German Pat. No. 601,392.
The cooling water pipes are fed from the bottom through distributing pipes and a tank, while at the top, they are in communication with the atmosphere over a pipe whose outlet is arranged above a drain.
In these methods, the coke can only be cooled in the cooling chamber in charges and not continuously and the cooling time is, as a rule, at least 3 to 4 hours, which requires a great number of cooling tanks per battery.
In addition to the above-mentioned methods, a method has also been suggested by German Patent Application No. P 29 52 065.8, filed on Dec. 22, 1979, wherein circulating gas for dry cooling is conducted directly in counterflow, and the cooling is also effected by means of indirect cooling surfaces. The coke is cooled in a round chamber with an antechamber, and the coke issues from the chamber through an opening in the center of the conical bottom.
This method and the necessary equipment have worked quite well on the whole. Some improvement, however, is still needed regarding the indirect heat transfer from the glowing coke to the cooling medium. This is due, to a certain extent, to the fact that the coke sinks at the edges in this arrangement until it issues from it.